BOISE, Idaho (AP) — An extension cord hooked to an electric grill on a porch shorted out and started a house fire that killed five people Saturday morning, a northern Idaho fire official says.

Orofino Fire Chief Mike Lee said the house was fully engulfed in flames when firefighters arrived after a neighbor reported the fire at 1:38 a.m.

He said smoke inhalation likely killed the two adults and three teens whose bodies were also badly burned in the blaze. He said the dead were a family of four plus a teenage friend who was sleeping over to help celebrate a birthday. He said he didn’t know the genders of the teens who died.

Lee said two of the teens attended the local school that houses 7th through 12th grade, and that one was home schooled. He declined to release names.

Autopsies are planned Monday, but he said there was no sign of foul play.

“It was an extension cord,” the chief said. “They had it plugged into an appliance and it wasn’t heavy enough to pack the load of the appliance and the cord shorted out.”

He said the house, a rental, didn’t have smoke alarms. He said three of the victims were found in bed.

He said neighbors reported the family using the electric grill at about 10 p.m. Friday, and that the family appears to have gone to bed by the time the fire started. He said he wasn’t sure if the electric grill was the type that had an off switch or heated up just by being plugged in.

“I would unplug it regardless,” he said.

Orofino is a town of just more than 3,000 people next to the Clearwater River in a mountainous part of the state known for its rugged beauty. The house where the fire took place is just a few blocks from the river.

Lee said the fire department has been in existence since 1911 and the only fire fatalities he could find in all that time occurred in 2007 in separate fires, so the five deaths are a big shock to the community.

“It’s sad,” he said. “I was just at the scene. There are already some teddy bears and flowers and things, a memorial put up there by some of the townspeople.”